1. Field of the Invention
The present invention relates to a control device for a vehicle including cruise control with an electronic throttle control system.
2. Description of the Related Art
Conventionally, a constant speed running control device for a motorcycle is known that automatically releases constant speed running control (cruise control) when a rider releases his/her hand from an accelerator grip during the constant speed running control (for example, see Patent Document 1 (Japanese Patent Laid-Open No. 58-137016)).
Also, a constant speed running control device for a motorcycle is known that automatically releases constant speed running control when a rider rotates an accelerator grip during the constant speed running control in addition to a brake operation and a clutch operation (for example, see Patent Document 2 (Japanese Patent Laid-Open No. 2001-246960)).
Techniques on cruise control of motorcycles have been conventionally developed, and a conventional constant speed running control device has been applied to a motorcycle including a cable throttle valve in which a throttle cable converts an operation amount of the accelerator grip into an opening degree of a throttle valve.
The conventional constant speed running control device fixes a position of a throttle pulley around which the throttle cable is wound or the throttle cable itself to maintain the opening degree of the throttle valve and performs cruise control when a predetermined switch such as a cruising vehicle speed set switch is operated while a motorcycle is running at a speed predetermined by a rider. Thus, the accelerator grip connected to the throttle valve via the throttle cable is also fixed in a position corresponding to the opening degree of the throttle valve.
In recent years, techniques on a so-called drive-by-wire motorcycle have been developed that includes an accelerator position sensor and electrically detects an operation amount of an accelerator grip to control an opening degree of a throttle valve.
A drive-by-wire electronic throttle control system does not include a throttle cable connecting the accelerator grip to the throttle valve. Thus, in the electronic throttle control system, the accelerator grip during cruise control is not fixed in a position corresponding to the opening degree of the throttle valve, but is generally placed in a fully closed position.
By such cruise control with the electronic throttle control system, even if a rider forgets the cruise control being performed because of careless driving or the like, and rotates the accelerator grip in a closing direction for deceleration, the accelerator grip has been already placed in the fully closed position and a further rotation operation cannot be performed. Thus, automatic release of the cruise control cannot be applied to the conventional constant speed running control device described in Patent Document 2. Then, a deceleration operation of the motorcycle during cruise control may be delayed.